Turbine wastegate

ABSTRACT

A turbocharger wastegate assembly includes a turbine housing that includes a chamber, a bore, two exhaust passages, a divider wall disposed between the two exhaust passages, and a wastegate seat, where the divider wall includes a divider wall surface; and a wastegate that includes a shaft, an arm and a plug, where the shaft is received by the bore of the turbine housing for rotation about an axis of the shaft to orient the plug in a closed state and to orient the plug in an open state, where, in the closed state, a contact portion of the plug contacts the wastegate seat and a shell portion of the plug defines a clearance with respect to the divider wall surface and extends into the two exhaust passages.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/420,306, filed 31 Jan. 2017 (U.S. Pat. No. 10,006,352, issued 26 Jun.2018), which is incorporated by reference herein, which is acontinuation of U.S. patent application Ser. No. 14/953,366, filed 29Nov. 2015 (U.S. Pat. No. 9,556,786, issued 31 Jan. 2017), which isincorporated by reference herein, which is a continuation of U.S. patentapplication Ser. No. 14/199,942, filed 6 Mar. 2014 (U.S. Pat. No.9,200,532, issued 1 Dec. 2015), which is incorporated by referenceherein, which is a continuation-in-part of U.S. patent application Ser.No. 13/974,326, filed 23 Aug. 2013 (U.S. Pat. No. 8,984,880, issued 24Mar. 2015), a continuation-in-part of U.S. patent application Ser. No.13/949,384, filed 24 Jul. 2013 (U.S. Pat. No. 9,010,109, issued 21 Apr.2015), and a continuation-in-part of U.S. patent application Ser. No.13/613,250, filed 13 Sep. 2012 (U.S. Pat. No. 8,904,785, issued 9 Dec.2014); all aforementioned U.S. Patent Applications are incorporated byreference herein.

TECHNICAL FIELD

Subject matter disclosed herein relates generally to turbomachinery forinternal combustion engines and, in particular, to turbine wastegates.

BACKGROUND

A turbine wastegate is typically a valve that can be controlled toselectively allow at least some exhaust to bypass a turbine. Where anexhaust turbine drives a compressor for boosting inlet pressure to aninternal combustion engine (e.g., as in a turbocharger), a wastegateprovides a means to control the boost pressure.

A so-called internal wastegate is integrated at least partially into aturbine housing. An internal wastegate typically includes a flappervalve (e.g., a plug), a crank arm, a shaft or rod, and an actuator. Aplug of a wastegate often includes a flat disk shaped surface that seatsagainst a flat seat (e.g., a valve seat or wastegate seat) disposedabout an exhaust bypass opening, though various plugs may include aprotruding portion that extends into an exhaust bypass opening (e.g.,past a plane of a wastegate seat).

In a closed position, a wastegate plug should be seated against awastegate seat (e.g., seating surface) with sufficient force toeffectively seal an exhaust bypass opening (e.g., to prevent leaking ofexhaust from a high pressure exhaust supply to a lower pressure region).Often, an internal wastegate is configured to transmit force from an armto a plug (e.g., as two separate, yet connected components). Duringengine operation, load requirements for a wastegate vary with pressuredifferential. High load requirements can generate high mechanicalstresses in a wastegate's kinematics components, a fact which has led insome instances to significantly oversized component design to meetreliability levels (e.g., as demanded by engine manufacturers).Reliability of wastegate components for gasoline engine applications isparticularly important where operational temperatures and exhaustpulsation levels can be quite high.

Various examples of wastegates and wastegate components are describedherein, which can optionally provide for improved kinematics, reducedexhaust leakage, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the various methods, devices,assemblies, systems, arrangements, etc., described herein, andequivalents thereof, may be had by reference to the following detaileddescription when taken in conjunction with examples shown in theaccompanying drawings where:

FIG. 1 is a diagram of a turbocharger and an internal combustion enginealong with a controller;

FIG. 2 is a series of view of an example of an assembly that includes awastegate;

FIG. 3 is a series of views of an example of an assembly that includes awastegate;

FIG. 4 is a cutaway view of the wastegate of FIG. 3;

FIG. 5 is a series of views of an example of a wastegate;

FIG. 6 is a view of the wastegate of FIG. 5;

FIG. 7 is a series of cutaway views of an example of an assembly thatincludes a wastegate;

FIG. 8 is a series of cutaway views of the example assembly of FIG. 7;

FIG. 9 is a series of cutaway views of a wastegate arm and plug in twodifferent orientations;

FIG. 10 is a series of cutaway views of a wastegate arm and plug in twodifferent orientations;

FIG. 11 is a series of diagrams of an example of a wastegate withrespect to fluid flow;

FIG. 12 is a series of views of an example of an assembly that includestwo scrolls;

FIG. 13 is a series of views of an example of an assembly that includestwo scrolls and an example of wastegate;

FIG. 14 is an example of an assembly that includes a wastegate;

FIG. 15 is a cutaway view of a portion of the assembly of FIG. 2;

FIG. 16 is a series of views of an example of a wastegate arm and plug;

FIG. 17 is a side view of the wastegate arm and plug of FIG. 16;

FIG. 18 is a cutaway view of an example of a turbine housing;

FIG. 19 is a series of diagrams of examples of wastegate arm and plugand profiles thereof;

FIG. 20 is a series of views of examples of profiles of a plug;

FIG. 21 is a series of views of examples of profiles of a seat; and

FIG. 22 is a series of views of examples of turbine wastegate plugs andseats.

DETAILED DESCRIPTION

Turbochargers are frequently utilized to increase output of an internalcombustion engine. Referring to FIG. 1, as an example, a system 100 caninclude an internal combustion engine 110 and a turbocharger 120. Asshown in FIG. 1, the system 100 may be part of a vehicle 101 where thesystem 100 is disposed in an engine compartment and connected to anexhaust conduit 103 that directs exhaust to an exhaust outlet 109, forexample, located behind a passenger compartment 105. In the example ofFIG. 1, a treatment unit 107 may be provided to treat exhaust (e.g., toreduce emissions via catalytic conversion of molecules, etc.).

As shown in FIG. 1, the internal combustion engine 110 includes anengine block 118 housing one or more combustion chambers thatoperatively drive a shaft 112 (e.g., via pistons) as well as an intakeport 114 that provides a flow path for air to the engine block 118 andan exhaust port 116 that provides a flow path for exhaust from theengine block 118.

The turbocharger 120 can act to extract energy from the exhaust and toprovide energy to intake air, which may be combined with fuel to formcombustion gas. As shown in FIG. 1, the turbocharger 120 includes an airinlet 134, a shaft 122, a compressor housing assembly 124 for acompressor wheel 125, a turbine housing assembly 126 for a turbine wheel127, another housing assembly 128 and an exhaust outlet 136. The housing128 may be referred to as a center housing assembly as it is disposedbetween the compressor housing assembly 124 and the turbine housingassembly 126. The shaft 122 may be a shaft assembly that includes avariety of components. The shaft 122 may be rotatably supported by abearing system (e.g., journal bearing(s), rolling element bearing(s),etc.) disposed in the housing assembly 128 (e.g., in a bore defined byone or more bore walls) such that rotation of the turbine wheel 127causes rotation of the compressor wheel 125 (e.g., as rotatably coupledby the shaft 122). As an example a center housing rotating assembly(CHRA) can include the compressor wheel 125, the turbine wheel 127, theshaft 122, the housing assembly 128 and various other components (e.g.,a compressor side plate disposed at an axial location between thecompressor wheel 125 and the housing assembly 128).

In the example of FIG. 1, a variable geometry assembly 129 is shown asbeing, in part, disposed between the housing assembly 128 and thehousing assembly 126. Such a variable geometry assembly may includevanes or other components to vary geometry of passages that lead to aturbine wheel space in the turbine housing assembly 126. As an example,a variable geometry compressor assembly may be provided.

In the example of FIG. 1, a wastegate valve (or simply wastegate) 135 ispositioned proximate to an exhaust inlet of the turbine housing assembly126. The wastegate valve 135 can be controlled to allow at least someexhaust from the exhaust port 116 to bypass the turbine wheel 127.Various wastegates, wastegate components, etc., may be applied to aconventional fixed nozzle turbine, a fixed-vaned nozzle turbine, avariable nozzle turbine, a twin scroll turbocharger, etc.

In the example of FIG. 1, an exhaust gas recirculation (EGR) conduit 115is also shown, which may be provided, optionally with one or more valves117, for example, to allow exhaust to flow to a position upstream thecompressor wheel 125.

FIG. 1 also shows an example arrangement 150 for flow of exhaust to anexhaust turbine housing assembly 152 and another example arrangement 170for flow of exhaust to an exhaust turbine housing assembly 172. In thearrangement 150, a cylinder head 154 includes passages 156 within todirect exhaust from cylinders to the turbine housing assembly 152 whilein the arrangement 170, a manifold 176 provides for mounting of theturbine housing assembly 172, for example, without any separate,intermediate length of exhaust piping. In the example arrangements 150and 170, the turbine housing assemblies 152 and 172 may be configuredfor use with a wastegate, variable geometry assembly, etc.

In FIG. 1, an example of a controller 190 is shown as including one ormore processors 192, memory 194 and one or more interfaces 196. Such acontroller may include circuitry such as circuitry of an engine controlunit (ECU). As described herein, various methods or techniques mayoptionally be implemented in conjunction with a controller, for example,through control logic. Control logic may depend on one or more engineoperating conditions (e.g., turbo rpm, engine rpm, temperature, load,lubricant, cooling, etc.). For example, sensors may transmit informationto the controller 190 via the one or more interfaces 196. Control logicmay rely on such information and, in turn, the controller 190 may outputcontrol signals to control engine operation. The controller 190 may beconfigured to control lubricant flow, temperature, a variable geometryassembly (e.g., variable geometry compressor or turbine), a wastegate(e.g., via an actuator), an electric motor, or one or more othercomponents associated with an engine, a turbocharger (or turbochargers),etc. As an example, the turbocharger 120 may include one or moreactuators and/or one or more sensors 198 that may be, for example,coupled to an interface or interfaces 196 of the controller 190. As anexample, the wastegate 135 may be controlled by a controller thatincludes an actuator responsive to an electrical signal, a pressuresignal, etc. As an example, an actuator for a wastegate may be amechanical actuator, for example, that may operate without a need forelectrical power (e.g., consider a mechanical actuator configured torespond to a pressure signal supplied via a conduit).

FIG. 2 shows an example of an assembly 200 that includes a turbinehousing 210 that includes a flange 211, a bore 212, an inlet conduit213, a turbine wheel opening 214, a spiral wall 215, an exhaust outletopening 216, a shroud wall 220, a nozzle 221, a volute 222 formed inpart by the spiral wall 215, a wastegate wall 223 that extends to awastegate seat 226, and an exhaust chamber 230. In the example of FIG.2, the turbine housing 210 may be a single piece or multi-piece housing.As an example, the turbine housing 210 may be a cast component (e.g.,formed via sand casting or other casting process). The turbine housing210 includes various walls, which can define features such as the bore212, the turbine wheel opening 214, the exhaust outlet opening 216, thechamber 230, etc. In particular, the wastegate wall 223 defines awastegate passage in fluid communication with the inlet conduit 213where a wastegate control linkage 240 and a wastegate arm and plug 250are configured for opening and closing the wastegate passage (e.g., forwastegating exhaust).

In the example of FIG. 2, the wastegate control linkage 240 includes abushing 242 configured for receipt by the bore 212 of the turbinehousing 210, a control arm 244 and a peg 246 and the wastegate arm andplug 250 includes a shaft 252, a shaft end 253, an arm 254 and a plug256. As shown, the bushing 242 is disposed between the bore 212 and theshaft 252, for example, to support rotation of the shaft 252, to sealthe chamber 230 from an exterior space, etc. The bore 212, the bushing242 and the shaft 252 may each be defined by a diameter or diameters aswell as one or more lengths. For example, the shaft 252 includes adiameter D_(s), the bore 212 includes a diameter D_(B) while the bushing242 includes an inner diameter D_(bi) and an outer diameter D_(bo). Inthe example of FIG. 2, when the various components are assembled, thediameters may be as follows: D_(B)>D_(bo)>D_(bi)>D_(s). As to lengths, alength of the shaft 252 exceeds a length of the bushing 242, whichexceeds a length of the bore 212. Such lengths may be defined withrespect to a shaft axis z_(s), a bushing axis z_(b) and a bore axisz_(B). As shown, the bushing 242 is disposed axially between a shoulderof the shaft 252 and the control arm 244 of the control linkage 240.

In the example of FIG. 2, a gap Δz is shown between a surface of thebushing 242 and a surface of the control arm 244, which allows for axialmovement of the shaft 252, for example, to facilitate self-centering ofthe plug 256 with respect to the wastegate seat 226.

As an example, the assembly 200 may be fitted to an exhaust conduit orother component of an internal combustion engine (see, e.g., examples ofFIG. 1) via the flange 211 such that exhaust is received via the inletconduit 213, directed to the volute 222. From the volute 222, exhaust isdirected via the nozzle 221 to a turbine wheel disposed in the turbinehousing 210 via the opening 214 to flow and expand in a turbine wheelspace defined in part by the shroud wall 220. Exhaust can then exit theturbine wheel space by flowing to the chamber 230 and then out of theturbine housing 210 via the exhaust outlet opening 216.

As to wastegating, upon actuation of the control linkage 240 (e.g., byan actuator coupled to the peg 246), the wastegate arm and plug 250 maybe rotated such that at least a portion of the received exhaust can flowin the wastegate passage defined by the wastegate wall 223, past thewastegate seat 226 and into the chamber 230, rather than through thenozzle 221 to the turbine wheel space. The wastegated portion of theexhaust may then exit the turbine housing 210 via the exhaust outletopening 216 (e.g., and pass to an exhaust system of a vehicle, berecirculated in part, etc.).

As an example, the control linkage 240 may exert a force that acts toforce the plug 256 in a direction toward the wastegate seat 226. Forexample, an actuator may include a biasing mechanism (e.g., a spring,etc.) that exerts force, which may be controllably overcome, at least inpart, for rotating the plug 256 away from the wastegate seat 226 (e.g.,for wastegating). As an example, an actuator may be mounted to aturbocharger (e.g., mounted to a compressor assembly, etc.). As anexample, an actuator may be a linear actuator, for example, thatincludes a rod that moves along an axis. Depending on orientation of aplug, a shaft, a control linkage and such a rod, to maintain the plug ina closed position, the rod may exert a downward force (e.g., away fromthe control linkage as in the example of FIG. 2) or the rod may exert anupward force (e.g., toward the control linkage). For example, where thecontrol arm 244 (e.g., and the peg 246) of the control linkage 240 areoriented on the same “side” as the plug 256 with respect to the shaft252, a downward force applied to the control arm 244 (e.g., via the peg246) may act to maintain the plug 256 in a closed position with respectto the wastegate seat 226; whereas, where, for example, an approximately180 degree span exists between a plug and a control arm, an upward forceapplied to the control arm may act to maintain the plug in a closedposition with respect to a wastegate seat.

As an example, a rod of an actuator may be biased to exert a force on acontrol linkage that causes the control linkage to exert a force on aplug (see, e.g., the plug 256) such that the plug seats against awastegate seat (see, e.g., the wastegate seat 226). In such an example,the actuator may at least in part overcome the force that biases the rodsuch that a shaft rotates the plug away from the wastegate seat. Forexample, in FIG. 2, to initiate wastegating, the entire plug 256 rotatesabout an axis of the shaft 252 and moves away from the wastegate seat226 (e.g., without any portion of the plug 256 moving into a wastegateopening defined by the wastegate seat 226). As an example, the movingaway of the plug 256 may be facilitated by exhaust pressure. Forexample, in a closed position, the plug 256 experiences a pressuredifferential where pressure is higher below the plug 256 and less abovethe plug 256. In such an example, the pressure below the plug 256 actsin a direction that is countered by the closing force applied to theplug 256 via the control linkage 240 (e.g., the pressure differentialacts to bias the plug 256 toward an open position). Accordingly, theclosing force applied to the plug 256 should overcome pressure forcefrom below the plug 256. Further, where the shaft 252 may include someplay (see, e.g., Δz, etc.), the closing force applied to the plug 256may cause the plug 256 to self-center with respect to the wastegate seat226 (e.g., to facilitate sealing, to avoid exhaust leakage, etc.).

In the example of FIG. 2, the axes of the bore 212, the bushing 242 andthe shaft 252 are shown as being aligned (e.g., defining a common axis),however, during assembly, operation, etc., some misalignment may occur.For example, over time, clearances between the various components (e.g.,plug, arm, shaft, bore, bushing, etc.) can change. Forces that can causesuch change include aerodynamic excitation, high temperatures,temperature cycling (e.g., temperatures <−20 degrees C. to >1000 degreesC.), chemical attack, friction, deterioration of materials, etc. For atleast the foregoing reasons, it can be difficult to maintain effectivesealing of a wastegate opening over the lifetime of an exhaust turbineassembly. As to temperature, problems at high temperatures generallyinclude wear and loss of function and consequently leakage, lack ofcontrollability or a combination of leakage and uncontrollability.

As an example, a plug may include a contact portion and a shell portion.For example, a plug may include a radiused portion as a contact portionthat contacts a surface of a wastegate seat in a closed state and ashell portion that defines a flow passage with respect to the surface ofthe wastegate seat in an open state. In such an example, the shellportion may extend into a wastegate passage in the closed state (e.g.,without contacting a surface that defines the wastegate passage, asurface of the wastegate seat, etc.). As an example, in an assembly,such a plug may be configured to self-center with respect to a wastegateseat (e.g., in a closed state). As an example, a surface of a wastegateseat may be conical, which may facilitate self-centering of a contactportion of a plug. As an example, one or more clearances may exist in anassembly for a wastegate shaft with respect to a bushing such that thewastegate shaft may move in a manner that allows for self-centering of awastegate plug, operatively coupled to the wastegate shaft, with respectto a wastegate seat.

FIG. 3 shows an example of an assembly 300 that includes a wastegate armand plug 350 that differs from the wastegate arm and plug 250 of theassembly 200 of FIG. 2. In particular, the wastegate arm and plug 350includes a plug 356 that includes a substantially hemispherical shellportion 357.

In the example of FIG. 3 the assembly 300 includes a turbine housing 310that includes a mounting flange 311, a bore 312, an inlet conduit 313, aturbine wheel opening 314, a spiral wall 315, an exhaust outlet opening316, a shroud wall 320, a nozzle 321, a volute 322 formed in part by thespiral wall 315, a wastegate wall 323 that defines (e.g., at least inpart) a wastegate passage 325 where the wastegate wall 323 extends to awastegate seat 326 that may be an interface between the wastegatepassage 325 and an exhaust chamber 330.

In the example of FIG. 3, the turbine housing 310 may be a single pieceor multi-piece housing. As an example, the turbine housing 310 may be acast component (e.g., formed via sand casting or other casting process).The turbine housing 310 includes various walls, which can definefeatures such as the bore 312, the turbine wheel opening 314, theexhaust outlet opening 316, the chamber 330, etc. In particular, thewastegate wall 323 defines at least in part the wastegate passage 325,which is in fluid communication with the inlet conduit 313 where awastegate control linkage 340 and the wastegate arm and plug 350 areconfigured for opening and closing the wastegate passage (e.g., forwastegating exhaust).

As an example, the assembly 300 may be fitted to an exhaust conduit orother component of an internal combustion engine (see, e.g., examples ofFIG. 1), for example, via a flange (see, e.g., the flange 211 of FIG. 2)such that exhaust is received via the inlet conduit 313, directed to thevolute 322. From the volute 322, exhaust is directed via the nozzle 321to a turbine wheel disposed in the turbine housing 310 via the opening314 to flow and expand in a turbine wheel space defined in part by theshroud wall 320. Exhaust can then exit the turbine wheel space byflowing to the chamber 330 and then out of the turbine housing 310 viathe exhaust outlet opening 316. As to wastegating, upon actuation of thecontrol linkage 340 (e.g., by an actuator coupled to the peg 346), thewastegate arm and plug 350 may be rotated such that at least a portionof the received exhaust can flow in the wastegate passage 325 (e.g., asdefined at least in part by the wastegate wall 323), past the wastegateseat 326 and into the chamber 330, rather than through the nozzle 321 tothe turbine wheel space. The wastegated portion of the exhaust may thenexit the turbine housing 310 via the exhaust outlet opening 316 (e.g.,and pass to an exhaust system of a vehicle, be recirculated in part,etc.).

In the example of FIG. 3, the wastegate control linkage 340 includes abushing 342 configured for receipt by the bore 312 of the turbinehousing 310, a control arm 344 and a peg 346 and the wastegate arm andplug 350 includes a shaft 352, a shaft end 353, an arm 354 and the plug356. As shown, the bushing 342 is disposed between the bore 312 and theshaft 352, for example, to support rotation of the shaft 352, to sealthe chamber 330 from an exterior space, etc. The bore 312, the bushing342 and the shaft 352 may each be defined by a diameter or diameters aswell as one or more lengths. For example, the shaft 352 includes adiameter D_(s), the bore 312 includes a diameter D_(B) while the bushing342 includes an inner diameter D_(bi) and an outer diameter D_(bo). Inthe example of FIG. 3, when the various components are assembled, thediameters may be as follows: D_(B)>D_(bo)>D_(bi)>D_(s). As to lengths, alength of the shaft 352 exceeds a length of the bushing 342, whichexceeds a length of the bore 312. Such lengths may be defined withrespect to a shaft axis z_(s), a bushing axis z_(b) and a bore axisz_(B).

In an enlarged cutaway view, the shaft 352 is shown as including an axisz_(s) that may become misaligned with an axis z_(b) of the bushing 342.For example, the bushing 342 may be received with minimal radialclearance with respect to the bore 312 of the housing 310 while a radialclearance may exist (e.g., a larger radial clearance) between the shaft352 and an inner surface of the bushing 342. In such a manner, the shaft352 may tilt with respect to the axis of the bushing 342 and, forexample, the axis of the bore 312. In the example of FIG. 3, contactpoints 359-1 and 359-2 are shown, which may determine a maximal extentof misalignment with respect to tilting of the axis of the shaft 352with respect to the axis of the bushing 342. As an example, such tiltmay be represented by a tilt angle Δϕ).

The enlarged cutaway view of FIG. 3 also shows an axial gap Δz thatexists between an outwardly facing end of the bushing 342 disposed at anaxial position and an inwardly facing surface of the control arm 344disposed at an axial position. In such an example, the axial gap may bedefined by the difference between these two axial positions. As shown inthe example of FIG. 3, the shaft 352 may be able to move axially wherethe axial distance may be limited in part by the end of the bushing 342,which defines, in part, the axial gap Δz. For example, the inwardlyfacing surface of the control arm 344 may contact the end of the bushing342, which, in turn, may limit axial inward movement of the shaft 352.

As illustrated in the example of FIG. 3, the shaft 352 may tilt and maymove axially where such movements may be limited (see, e.g., Δz and Δϕ).As an example, the wastegate arm and plug 350 may act to self-centerwith respect to the wastegate seat 326 responsive to force applied tothe control arm 344 (e.g., which is transmitted to the wastegate arm andplug 350 via the shaft 352). In such an example, self-centering mayoccur for effective sealing of the wastegate within the range ofclearances that allow for axial and/or angular movement of the shaft352.

As an example, during operational use, one or more clearances betweenvarious components (e.g., plug, arm, shaft, bore, bushing, etc.) maychange. Forces that can cause such change include aerodynamicexcitation, high temperatures, temperature cycling (e.g., temperatures<−20 degrees C. to >1000 degrees C.), chemical attack, friction,deterioration of materials, etc. For at least the foregoing reasons, itmay be difficult to maintain effective sealing of a wastegate openingover the lifetime of an exhaust turbine assembly. As to temperature,problems at high temperatures generally include wear and loss offunction and consequently leakage, lack of controllability or acombination of leakage and uncontrollability.

As mentioned, the wastegate arm and plug 350 differs from the wastegatearm and plug 250. In particular, the plug 356 differs from the plug 256.Further, the shape of the arm 354 differs from the shape of the arm 254.In an assembly such as the assembly 200 or the assembly 300, due to oneor more factors, the wastegate arm and plug 350 may enhance performance,controllability, longevity, etc. when compared to the wastegate arm andplug 250.

As an example, the wastegate arm and plug 350 may be shaped with respectto the wastegate seat 326 to provide for effective sealing withinamounts of known machined and assembled clearances and, for example,within amounts of additional clearances that may occur responsive towear, temperature, etc.

As an example, the wastegate arm and plug 350 may be a unitary wastegatearm and plug (e.g., a monoblock wastegate arm and plug) or a wastegatearm and plug assembly. In contrast, a multicomponent arm and plugassembly includes interfaces between components. Such interfaces may besubject to wear, deformation, etc., which may interfere with properoperation over time.

As an example, the wastegate arm and plug 350 may have a lesser massthan the wastegate arm and plug 250 and, for example, a center of massfor the wastegate arm and plug 350 may differ compared to a center ofmass for the wastegate arm and plug 250. As an example, due to the shapeof the plug 356, it may perform aerodynamically in a more beneficialmanner than the plug 256. For example, the plug 356 may, due to itsshape, act to maintain its center more effectively than the plug 256. Asan example, the wastegate arm and plug 350 may provide benefits as tocontrollability, for example, due to centering, reduces chatter,aerodynamics, etc. As an example, such benefits may improve performance,longevity, etc. of an actuator that is operatively coupled to thewastegate arm and plug 350 (e.g., for transitioning states, maintaininga state, etc.). As an example, such benefits may improve performance,longevity, etc. of a seal mechanism (e.g., bushing, bushings, etc.) forthe shaft 352 of the wastegate arm and plug 350 (e.g., with respect to abore).

FIG. 4 shows an enlarged view of a portion of the assembly 300 of FIG.3. As shown in the example of FIG. 4, the plug 356 includes asubstantially hemispherical shell portion 357. As an example, aspherical shell may be defined as a generalization of an annulus tothree dimensions. As an example, a spherical shell may be defined as aregion between two concentric spheres of differing radii. As an example,a hemispherical shell may be defined as a region between two hemispheresof differing radii. As an example, a substantially hemispherical shellmay include a portion that may be defined by a portion of a firsthemisphere and a portion of a second hemisphere.

As an example, a substantially hemispherical shell may have a center ofmass (e.g., geometric centroid) that may be approximated as lying at adistance d along an axis from a base plane where the distance may bedefined by a first radius r1 and a second radius r2. For example, thedistance d may be defined as 3(r2 ⁴−r1 ⁴)/8(r2 ³−r1 ³). In comparison,the center of mass (e.g., geometric centroid) of a uniform solidhemisphere of radius r lies on the axis of symmetry at a distance of3r/8 from the base. As to volume, the volume of a solid hemisphere is⅔πr³ and the volume of a hemispherical shell may be calculated bysubtracting the volume of two hemispheres. As an example, a solidhemisphere with a radius of 1 cm may have a center of mass at about0.375 cm from a base plane and a volume of about 2.1 cubic centimetersand a hemispherical shell with an outer radius of 1 cm and an innerradius of 0.8 cm may have a center of mass at about 0.45 cm from a baseplane and a volume of about 1 cubic centimeter. Thus, in such anexample, while the center of mass may be extended for the hemisphericalshell with respect to the solid hemisphere, the overall mass is aboutone half that of the solid hemisphere. In such an example, where a plugis fashioned as a hemispherical shell rather than a solid hemisphere,the reduction in overall mass may be beneficial as to performance,controllability, etc. (e.g., the reduction in mass may overcome anydetriment from a slight increase in center of mass away from a baseplane, which may include an axis of rotation of a shaft).

FIG. 5 shows an example of the wastegate arm and plug 350 that may beincluded in an assembly (e.g., an assembly that includes multiplewastegate passages, a bridge or divider across a wastegate passage,etc.). As an example, the wastegate arm and plug 350 may be made ofmaterial (e.g., metal, alloy, etc.) suitable for temperaturesexperienced during operation of an exhaust turbine (e.g., of aturbocharger).

In the example of FIG. 5, the wastegate arm and plug 350 includes theshaft 352 that includes a diameter D_(s) over a length Δz_(s), the arm354 that extends axially outwardly away from the shaft 352 from ashoulder 355 and radially downwardly to the plug 356, which includes thesubstantially hemispherical shell portion 357. An axial dimension Δz_(a)is shown in the example of FIG. 5 as being a distance from the shoulder355 to a centerline of the plug 356. The plug 356 is shown as having anouter diameter D_(po). As an example, the centerline of the plug 356 maydefine or coincide with an x-axis that may, for example, be used as areference to describe features of the arm 354, the plug 356, angles ofrotation of the arm 354 and the plug 356, etc.

FIG. 6 shows a top plan view of the wastegate arm and plug 350 of FIG.5. As shown, a surface of the plug 356 may be defined in part by aninner radius or radii, for example, as measured from an axis (see alsodashed line in FIG. 5). Such a surface may define, in part, a shell suchas, for example, a spherical cap shell, a substantially hemisphericalshell, etc.

FIG. 7 shows a portion of an example of an assembly 700 that includes aturbine housing 710 that includes a bore 712, a wastegate passage 725, awastegate seat 726, a chamber 730 and a wastegate arm and plug 750. Asshown in FIG. 7, the wastegate arm and plug 750 includes a shaft 752, ashaft end 753, an arm 754 that extends from the shaft 752, a plug 756that extends from the arm 754 and a substantially hemispherical shellportion 757 that extends from the plug 756.

In the example of FIG. 7, contact regions are indicated with respect toa shaft side and a free side (see, e.g., C_(SS) and C_(FS)). As shown,the plug 756 contacts the wastegate seat 726 at a distance below anupper edge of the wastegate seat 726 (see, e.g., C_(FS)) and contactsthe wastegate seat 726 at a distance above a lower edge of the wastegateseat 726 (see, e.g., C_(SS)). As an example, a surface of contact may bedefined with respect to the wastegate seat 726 and a surface of contactmay be defined with respect to the plug 756.

As an example, force applied to the wastegate arm and plug 750 mayovercome exhaust pressure in the passage 725 (e.g., a pressuredifferential between the passage 725 and the chamber 730) and such forcemay cause the plug 756 to self-center with respect to the wastegate seat726 to provide an effective seal (e.g., minimal leakage of exhaust fromthe passage 725 to the chamber 730). As mentioned, clearances may existthat allow for some movement of the shaft 752 with respect to thebushing 742 and, for example, the bore 712. As an example, the plug 756and the wastegate seat 726 may be shaped to provide for effectivesealing via some amount of self-centering of the plug 756, for example,within clearance(s) that may exist that allow for movement of the shaft752. In other words, clearances may exist that allow for shaft movementthat allows for self-centering of a plug with respect to a wastegateseat (e.g., for purposes of achieving effective sealing).

FIG. 8 shows cutaway views of the assembly 700 of FIG. 7 for the plug756 in a closed position and in an open position with respect to thewastegate seat 726. Such views illustrate how a flow passage (e.g.,opening between the passage 725 and the chamber 730) may be shaped bythe substantially hemispherical shell portion 757 of the wastegate armand plug 750.

FIG. 8 also shows various examples of dimensions. For example, thewastegate seat 726 may be defined in part by a cone angle (γ). As anexample, a relationship between the wastegate seat 726 and thesubstantially hemispherical shell portion 757 may be defined by anopening angle (δ).

In the example of FIG. 8, open regions are indicated with respect to ashaft side and a free side (see, e.g., O_(SS) and O_(FS)). These regionsexist in three-dimensions, for example, as an annulus with a shape thatdepends on angle about a central axis of the wastegate seat 726. Asshown in the example of FIG. 8, exhaust may flow via these open regions(see, e.g., open-headed arrows).

FIGS. 9 and 10 shows some additional examples of clearances and possiblemovements for the wastegate arm and plug 250, noting that such movementsmay optionally occur for one or more other arrangements described herein(e.g., depending on clearances, etc.).

FIG. 9 shows two displaced orientations 910 and 930 of the wastegate armand plug 250 within the assembly 200, in particular, where the axis ofthe shaft 252 of the wastegate arm and plug 250 is not aligned with, forexample, the axis of the bore 212 (e.g., and the axis of the bushing 242disposed in the bore 212).

In the orientations 910 and 930, contact exists between the plug 256 andthe wastegate seat 226. In particular, contact exists between a radiusedportion (e.g., toroidal portion) of the plug 256 and a conical portionof the wastegate seat 226. As an example, the orientations 910 and 930may represent maximum angular misalignments with respect to a bore axisof a bore (e.g., ±5 degrees), for example, where some angularmisalignment with respect to a bushing axis of a bushing disposed in thebore (e.g., ±1 degree). As mentioned, for a variety of reasons, somemisalignment may occur (e.g., during assembly, during operation, etc.).For example, FIG. 3 shows a tilt angle (Δϕ) for the shaft 352 withrespect to the bushing 342 and, for example, the bore 312.

FIG. 10 shows two displaced orientations 1010 and 1030 of the wastegatearm and plug 250 within the assembly 200, in particular, where the axisof the shaft 252 of the wastegate arm and plug 250 is not aligned with,for example, the axis of the bore 212 (e.g., and the axis of the bushing242 disposed in the bore 212).

In the orientations 1010 and 1030, contact exists between the plug 256and the wastegate seat 226. In particular, contact exists between aradiused portion (e.g., toroidal portion) of the plug 256 and a conicalportion of the wastegate seat 226. As an example, the orientations 1010and 1030 may represent maximum displacement misalignments (e.g., Δ) withrespect to a bore axis of a bore (e.g., ±1.6 mm), for example, wheresome displacement misalignment with respect to a bushing axis of abushing disposed in the bore (e.g., ±0.1 mm). As mentioned, for avariety of reasons, some misalignment may occur (e.g., during assembly,during operation, etc.). For example, FIG. 3 shows a tilt angle (Δϕ) forthe shaft 352 with respect to the bushing 342 and, for example, the bore312.

As an example, a wastegate arm and plug may include extreme positionsinside a bushing disposed in a bore of a turbine housing while beingable to maintain contact with a wastegate seat for purposes of sealing awastegate passage (e.g., adequate sealing for acceptable performance).For example, the toroidal portion of the plug 356 (e.g., or the plug756) may act to maintain contact with a wastegate seat.

FIG. 11 shows examples of plots 1110 and 1130 of trial data for awastegate arm and plug in an assembly. As shown in FIG. 11, the plot1110 is a pressure contour plot for an open angle of about 20 degrees.In the plot 1110, a series of filled circles approximate locations ofpoints (e.g., stagnation points or pressure maxima) over a range ofangles from about 2.5 degrees open to about 30 degrees open (e.g.,without correction of perspective of the plug). The plot 1130 shows flowstreamlines as well as pressure contours, for example, to illustrate howexhaust flows through a plug-seat clearance for an open angle of about20 degrees. As mentioned, a high pressure may correspond to a stagnationpoint about which flow is diverted radially outwardly to flow through aplug-seat clearance. As mentioned, for at least some open angles, both atoroidal portion of a plug and a modified sphere portion of a plug maydefine a plug-seat clearance. As open angle changes, the shape of theplug-seat clearance also changes. As illustrated in the example of FIG.11, the locations of pressure maxima experienced by a plug over a rangeof open angles may be “controlled” at least in part by shape of the plugand, for example, at least in part by shape of a wastegate seat.

As an example, in fluid dynamics, a stagnation point may be a point in aflow field where local velocity of fluid is approximately zero. Astagnation point may exist at a surface of an object in a flow field,for example, where fluid is brought to rest by presence of the object inthe flow field (e.g., consider a bluff body in a flow field). As anexample, the Bernoulli equation may demonstrate how static pressure ishighest where velocity is zero (e.g., such that static pressure or“stagnation pressure” may be at its maximum value at a stagnationpoint). Where the object is movable in a flow field via an actuator, thepressure experienced by the object may be transmitted to the actuator.If a movable object “catches” wind while being moved by an actuator(e.g., a sharp transition such as a step transition in pressure), theactuator may be impacted as well. As an example, the shape of the plug356 may help reduce impact on an actuator as the actuator rotates theplug 356 with respect to a wastegate opening that provide for flow ofexhaust.

As an example, the plug 356 (e.g., or the plug 756) may be configuredwith two plug portions, for example, that extend from a lower surface ofthe plug 356 (e.g., consider a cutting plane that cuts the plug 356 toform a plane from which two plug portions extend downwardly therefrom).As an example, such plug portions may act to seal multiple exhaustpassages (e.g., multiple wastegate passages) while plug portions (e.g.,extensions) may extend into such passages to form clearances to directexhaust flow (e.g., such plug portions may be configured to not contacta turbine housing, a wastegate passage wall, etc.).

For example, in FIG. 5, the plug 356 may including two plug portionsextending axially outward in a direction of the x-axis (e.g., a distanceΔX_(p)), for example, from a toroidal portion of the plug 356 defined atleast in part by a radius r_(T) where, for example, a perimeter of theplug portions is less than a circumference having a diameter D_(T)associated with the toroidal portion of the plug 356 (e.g., in aprojected view, the perimeter may be within the circumference). As anexample, a plug may include a first plug portion shaped approximately asa quarter of a sphere and a second plug portion shaped approximately asa quarter of a sphere.

As an example, a plug may include two plug portions with a spacingbetween the two plug portions that may be, for example, orientedorthogonally to a shaft of a wastegate arm and plug. In such an example,rotation of the wastegate arm and plug about a rotational axis of theshaft can ensure alignment of the spacing with respect to a divider thatdivides two openings into which the two plug portions may extend.Receipt of the plug portions by two openings can allow a toroidalportion of a plug (see, e.g., the plug 356) to seat in a single seatthat serves as part of a sealing mechanism for the two openings.

As an example, plug portions may enhance operational dynamics (e.g.,fluid dynamics) associated with two openings while another portion of aplug that acts to seal both openings (e.g., via a common valve seat).

As an example, a plug portion may include a spherical wedge shape thatincludes a spherical lune surface. A spherical lune is a portion of asurface of a sphere of radius r cut out by two planes through theazimuthal axis with a dihedral angle. As an example, a dihedral angle ofa plug portion may be in a range from about 45 degrees to about 90degrees. As an example, a plug may include symmetric plug portions whereeach plug portion may be defined by a dihedral angle (e.g., +90 degreesand −90 degrees). As an example, two plug portions may be spaced fromeach other, for example, to accommodate a divider therebetween, whichmay be a wall that divides two passages.

As an example, a plug portion may be shaped as a modified sphericallune. For example, a modified spherical lune may be a wedge of aspherical cap, a wedge of a modified spherical cap, or a modified wedgeof a spherical cap. For example, a plug may be defined as having a shapelike a spherical cap with a cut-out portion that forms two spaced apartwedges where the spacing between the wedges can accommodate a divider.

FIG. 12 shows an example of a twin scroll turbine assembly 1200 that maybe configured to receive exhaust from a manifold 1201 that includes atwo separate exhaust passages, each with its own opening 1202-1 and1202-2. The assembly 1200 includes a housing 1210 that includes a wall1215 that defines two scrolls 1222-1 and 1222-2 (e.g., two volutes) thatcan direct exhaust to a turbine wheel space, for example, via a nozzleor nozzles 1221. As an example, a turbine wheel space may be defined inpart by a shroud wall 1220 located axially above the nozzle or nozzles1221 that extends axially to an exhaust chamber 1030.

In the example of FIG. 12, the housing 1210 includes two wastegate walls1223-1 and 1223-2 associated with respective scrolls 1222-1 and 1222-2.The two wastegate walls 1023-1 and 1023-2 form openings about whichexists a wastegate seat 1226. As shown, the wastegate wall 1223-1defines a first wastegate passage in fluid communication with a firstinlet conduit and the wastegate wall 1223-2 defines a second wastegatepassage in fluid communication with a second inlet conduit where, forexample, the inlet conduits may be operatively coupled to respectiveopenings 1202-1 and 1202-2 of the manifold 1201. As an example, themanifold 176 of FIG. 1 may be configured to be a divided manifold, forexample, where the turbine housing assembly 172 may include twin scrolls(e.g., two volutes). As an example, the cylinder head 154 of FIG. 1 mayinclude divided passages, for example, where the turbine housingassembly 152 may include twin scrolls (e.g., two volutes).

For control of exhaust flow through the wastegate passages, the assembly1200 includes a wastegate control linkage 1240 and a wastegate arm andplug 1250 with an arm component 1254 and a plug component 1256 that areconfigured for opening and closing the wastegate passages (e.g., forwastegating exhaust) via seating of the plug component 1256 with respectto the wastegate seat 1026.

The assembly 1200 may be described, for example, with respect to variousaxes. For example, consider an axis of a turbine wheel space that maycoincide with a rotational axis of a turbine wheel, an axis of a shaftof the wastegate arm and plug 1250 and an axis of the plug component1256. Further, each of the openings of the wastegate passages may bedefined by a respective axis, for example, where in a closed state ofthe wastegate, the axis of the plug component 1056 is approximatelyaligned parallel to the axes of the openings of the wastegate passages.

As an example, the manifold 1201 may be considered a divided manifoldthat separates flow of exhaust from cylinders whose cycles may interferewith one another (e.g., as to exhaust pulse energy). For example, on afour-cylinder engine with firing order 1-3-4-2, cylinder #1 is endingits expansion stroke and opening its exhaust valve while cylinder #2still has its exhaust valve open (cylinder #2 is in its overlap period).In an undivided exhaust manifold, a pressure pulse from cylinder #1'sexhaust blowdown event may be more likely to contaminate cylinder #2with high pressure exhaust gas, which can impact performance of cylinder#2's (e.g., ability to breathe properly) and diminish pulse energy thatmay have been better utilized in by a turbine. As an example, a propergrouping for the aforementioned engine may keep complementary cylindersgrouped together (e.g., exhaust of cylinders #1 and #4 as onecomplementary group and cylinders #2 and #3 as another complementarygroup). Such an approach may better utilize exhaust pulse energy and,for example, improve turbine performance (e.g., increase boost morerapidly).

Referring again to the assembly 1200, pulse energy may differ in the twopassages 1223-1 and 1223-2 such that one portion of the plug component1256 experiences different force than another portion of the plug 1256.Such differences may cause vibration, misalignment, wear, etc. Forexample, as the plug component 1256 includes a stem seated in an openingof the arm component 1254, pressure may cause the plug component 1256 totilt such that an axis of the stem misaligns with respect to an axis ofthe opening of the arm component 1254. Over time, wear may occur (e.g.,increased clearances), which may exacerbate wear, leakage, etc.

As to leakage, leakage may occur from a passage to the chamber 1030and/or from one passage to another passage (e.g., and vice versa). Forexample, due to a pressure difference between the passages, exhaust mayflow from the passage formed by the wall 1223-1 to the passage formed bythe wall 1223-2 in a space above a divider wall surface 1217 and theplug component 1256. Such flow may act to “equalize” pressures, whichmay, for example, be detrimental to a divided manifold approach (e.g.,or a twin scroll approach). Such flow may be referred to asscroll-to-scroll leakage that occurs for a closed operational state of awastegate arm and plug (e.g., where a controller, actuator, etc. callsfor the passages to be closed).

FIG. 13 shows two cutaway views of an example of an assembly 1300 thatincludes a housing 1310 and a wastegate arm and plug 1350 and shows aperspective view of an example of a wastegate seat 1326. As an example,the wastegate arm and plug 1350 in conjunction with the wastegate seat1326 may provide for a more progressive flow through a wastegate duringwastegate valve opening. As an example, the wastegate seat 1326 may bedefined in part by a conical surface.

As shown in the example of FIG. 13, the housing 1310 includes awastegate walls 1323-1 and 1323-2 that extend to the wastegate seat 1326and includes an exhaust chamber 1330. In the example of FIG. 13, theturbine housing 1310 may be a single piece or multi-piece housing. As anexample, the turbine housing 1310 may be a cast component (e.g., formedvia sand casting or other casting process). As an example, the housing1310 may be made of material (e.g., metal, alloy, etc.) suitable fortemperatures experienced during operation of an exhaust turbine (e.g.,of a turbocharger).

The turbine housing 1310 includes various walls, which can definefeatures such as a bore, a turbine wheel opening, an exhaust outletopening, etc. In particular, in the example of FIG. 13, the wastegatewalls 1323-1 and 1323-2 define wastegate passages in fluid communicationwith inlet conduits (e.g., associated with a divided manifold) where awastegate control linkage and a wastegate arm and plug 1350 areconfigured for opening and closing the wastegate passages (e.g., forwastegating exhaust). As an example, the assembly 1300 may include abushing 1342 (see, e.g., dashed lines) that may be disposed in the boreof the turbine housing 1310 and that may abut the shoulder 1355 of thewastegate arm and plug 1350 (see, e.g., the bushing 242 of the assembly200, the bushing 342 of the assembly 300, etc.).

In the perspective view, an example shape for the wastegate seat 1326 isillustrated, for example, where a seat depth (e.g., from the exhaustchamber 1330 to the space defined by the wastegate walls 1323-1 and1323-2) may be greater on a shaft side (see, e.g., As) than on a frontside. As shown a divider wall surface 1317 is disposed, for example, atan axial location that is about the level of a lower edge of the conicalshaped wastegate seat 1326. As shown in the cutaway view, the two plugportions 1357 and 1359 descend below the divider wall surface 1317(e.g., of the wall 1315) to form an approximately inverted U-shapedclearance, which may offer resistance to flow of exhaust betweenpassages formed by the walls 1323-1 and 1323-2. Referring again to theassembly 1200 of FIG. 12, a clearance exists between the divider wallsurface 1217 and the plug 1256 that does not offer such resistance toflow of exhaust between passages formed by the walls 1223-1 and 1223-2(e.g., a flow may occur directly across the divider wall surface 1317).As an example, resistance to exhaust flow between such passages may helppreserve benefits provided by a divided manifold operatively coupled toa twin scroll turbine housing (e.g., of a turbocharger).

FIG. 13 shows how a toroidal portion and two plug portions 1357 and 1359of the plug 1356 may be oriented with respect to the wastegate seat1326, which may be a conical seat. As shown, the toroidal portion of theplug 1356 can seat against the wastegate seat 1126 when the wastegatearm and plug 1350 is in a closed position. Further, in a closedposition, a clearance exists about each of the two plug portions 1357and 1359 (e.g., the two plug portions 1357 and 1359 do not contact thewastegate seat 1326).

As shown in a lower cutaway view, when the wastegate arm and plug 1350is in an open position of approximately 5 degrees (e.g., about 5 degreesof rotation of the shaft 1352 in a bore of the housing 1310), surfacesof the two plug portions 1357 and 1359 of the plug 1356 defineclearances with respect to the wastegate seat 1326 (see, e.g., frontside and shaft side arrows). Where a pressure differential exists (e.g.,higher pressure on the wastegate wall side 1323-1 and/or 1323-2),exhaust may flow through the clearances where characteristics of suchflow is determined, in part, by the surfaces of the two plug portions1357 and 1359 of the plug 1356 and, in part, by the surface of thewastegate seat 1326. For example, flow may impinge against the surfacesof the two plug portions 1357 and 1359 of the plug 1356, for example, toform a stagnation point on each of the two plug portions 1357 and 1359about which flow is diverted radially outwardly therefrom and, forexample, toward a clearance between the plug 1356 and the wastegate seat1326.

Further, as shown in the example of FIG. 13, on a shaft side of the plug1356, the toroidal portion of the plug 1356 also defines a clearancewith respect to the wastegate seat 1326 (e.g., where rotation rotatesthe front side of the plug 1356 a greater arc distance than the shaftside of the plug 1356). Accordingly, in the example of FIG. 13, for theassembly 1300, both the toroidal portion and the two plug portions 1357and 1359 of the plug 1356 define clearances with respect to thewastegate seat 1326 of the housing 1310. These clearances (e.g., over arange of “open” angles), act to “control” characteristics of exhaustflow. For example, flow characteristics may be controlled byinter-component clearance shapes over a range of open angles in a mannerthat enhances controllability of a wastegate. As an example, theassembly 1300 may provide for a monotonic and smooth evolution ofpressure with respect to wastegate valve opening where suchcharacteristics enhance controllability of the wastegate valve. Such anapproach may particularly enhance control where a wastegate valveactuator is a mechanical vacuum actuator (e.g., an actuator to rotate awastegate arm and plug with respect to a wastegate seat).

As an example, an assembly such as the assembly 1300 may be operativelycoupled to a manifold such as the manifold 1201 of FIG. 12 or themanifold 176, which may be a divided manifold. As an example, anassembly such as the assembly 1300 may be operatively coupled to acylinder head such as the cylinder head 154 of FIG. 1, for example,where passages 156 may be divided (e.g., twin passages) within thecylinder head 154 to direct exhaust from respective cylinders (e.g.,complementary group #1 and #4 and complementary group #2 and #3) to theassembly (e.g., to respective scrolls of a twin scroll housing).

As to stagnation points, which may be points of maximum pressure (e.g.,force) upon the plug 1356 of the wastegate arm and plug 1350, these maybe located relatively centrally during opening of the wastegate. In suchan example, forces exerted upon the plug 1356 may be more effectivelytransferred to the arm 1354 and the shaft 1352, which, in turn, may actto diminish vibration, misalignment, etc.

As an example, the shape of the plug 1356 (e.g., via the two plugportions 1357 and 1359) may help reduce impact on an actuator as theactuator rotates the plug 1356 with respect to a wastegate opening thatprovide for flow of exhaust.

In the example assembly 1300, the wastegate arm and plug 1350 mayinclude a shoulder that seats at or proximate to a surface of thehousing 1310 (e.g., such that the shaft 1352 may not be visible in theviews of FIG. 13). As an example, the assembly 1300 may include abushing (see, e.g., dashed lines of the bushing 1342 in FIG. 11) suchas, for example, the bushing 242 of the assembly 200, the bushing 342 ofthe assembly 300, etc. For example, such a bushing may be disposed in abore of a housing and extend to the shoulder 1355 of the wastegate armand plug 1350.

Various views of FIGS. 12 and 13 are shown as “see-through” cutawayviews where solid walls may be shown as being hollow, for example, tomore clearly illustrate contours of such walls, shapes of passages, etc.

FIG. 14 shows an example of an assembly 1400 that includes an actuator1401, an actuation rod 1402, an actuator linkage 1403, a center housing1407 (e.g., to house a bearing, bearings, etc. for a turbocharger shaft,etc.), a compressor housing 1409, a turbine housing 1410 that includes abore 1412, a spiral wall 1415 (e.g., that defines, in part, a volute),an exhaust outlet opening 1416, a wastegate wall 1423 that extends to awastegate seat 1426, and an exhaust chamber 1430.

In the example of FIG. 14, the turbine housing 1410 may be a singlepiece or multi-piece housing. As an example, the turbine housing 1410may be a cast component (e.g., formed via sand casting or other castingprocess). As shown, the turbine housing 1410 includes various walls,which can define features such as the bore 1412, a turbine wheelopening, an exhaust outlet opening, the chamber 1430, etc. Inparticular, the wastegate wall 1423 defines a wastegate passage in fluidcommunication with an inlet conduit where a wastegate control linkage1440 and a wastegate arm and plug 1450 are configured for opening andclosing the wastegate passage (e.g., for wastegating exhaust).

In the example of FIG. 14, the wastegate control linkage 1440 includes abushing 1442 configured for receipt by the bore 1412 of the turbinehousing 1410, a control arm 1444 and a peg 1446 and the wastegate armand plug 1450 includes a shaft 1452, a shaft end 1453, an arm 1454 and aplug 1456 (see, e.g., the wastegate arm and plug 250, 350, 750, etc.).As shown, the bushing 1442 is disposed between the bore 1412 and theshaft 1452, for example, to support rotation of the shaft 1452, to sealthe chamber 1430 from an exterior space, etc. The bore 1412, the bushing1442 and the shaft 1452 may each be defined by a diameter or diametersas well as one or more lengths.

As an example, the assembly 1400 may be fitted to an exhaust conduit orother component of an internal combustion engine (see, e.g., examples ofFIG. 1) via a flange such that exhaust is received via an inlet conduitthat may direct exhaust to a volute (e.g., or volutes) that may bedefined at least in part by the spiral wall 1415. As an example, avolute (e.g., or volutes) may direct exhaust (e.g., via a nozzle ornozzles) to a turbine wheel disposed in the turbine housing 1410 wherethe exhaust may flow and expand in a turbine wheel space defined in partby the turbine housing 1410. Exhaust may then exit the turbine wheelspace by flowing to the chamber 1430 and then out of the turbine housing1410 via the exhaust outlet opening 1416.

As to wastegating, upon actuation of the control linkage 1440 (e.g., bythe actuator linkage 1403 being operatively coupled to the peg 1446),the wastegate arm and plug 1450 may be rotated such that at least aportion of the received exhaust can flow in the wastegate passagedefined by the wastegate wall 1423, past the wastegate seat 1426 andinto the chamber 1430, rather than through a nozzle to a turbine wheelspace. The wastegated portion of the exhaust may then exit the turbinehousing 1410 via the exhaust outlet opening 1416 (e.g., and pass to anexhaust system of a vehicle, be recirculated in part, etc.).

As an example, the control linkage 1440 may exert a force that acts toforce the plug 1456 in a direction toward the wastegate seat 1426. Forexample, the actuator 1401 may include a biasing mechanism (e.g., aspring, etc.) that exerts force, which may be controllably overcome, atleast in part, for rotating the plug 1456 away from the wastegate seat1426 (e.g., for wastegating). As an example, the actuator 1401 may bemounted to the assembly 1400. As an example, the actuator 1401 may be alinear actuator, for example, for moving the rod 1402 along an axis.Depending on orientation of a plug, a shaft, a control linkage and sucha rod, to maintain the plug in a closed position, the rod may exert adownward force (e.g., away from the control linkage as in the example ofFIG. 14) or the rod may exert an upward force (e.g., toward the controllinkage). For example, where the control arm 1444 (e.g., and the peg1446) of the control linkage 1440 are oriented on the same “side” as theplug 1456 with respect to the shaft 1452, a downward force applied tothe control arm 1444 (e.g., via the peg 1446) may act to maintain theplug 1456 in a closed position with respect to the wastegate seat 1426;whereas, where, for example, an approximately 180 degree span existsbetween a plug and a control arm, an upward force applied to the controlarm may act to maintain the plug in a closed position with respect to awastegate seat.

As an example, the rod 1402 of the actuator 1401 may be biased to exerta force on the control linkage 1440 that causes the control linkage 1440to exert a force on the plug 1456 such that the plug 1456 seats againstthe wastegate seat 1426. In such an example, the actuator 1401 may atleast in part overcome the force that biases the rod 1402 such that theshaft 1452 rotates the plug 1456 away from the wastegate seat. Forexample, in FIG. 14, to initiate wastegating, the entire plug 1456rotates about an axis of the shaft 1452 and moves away from thewastegate seat 1426 (e.g., without any portion of the plug 1456 movinginto a wastegate opening defined by the wastegate seat 1426). As anexample, the moving away of the plug 1456 may be facilitated by exhaustpressure. For example, in a closed position, the plug 1456 experiences apressure differential where pressure is higher below the plug 1456 andless above the plug 1456. In such an example, the pressure below theplug 1456 acts in a direction that is countered by the closing forceapplied to the plug 1456 via the control linkage 1440 (e.g., thepressure differential acts to bias the plug 1456 toward an openposition). Accordingly, the closing force applied to the plug 1456should overcome pressure force from below the plug 1456. Further, wherethe shaft 1452 may include some play (e.g., axial play, etc.), theclosing force applied to the plug 1456 may cause the plug 1456 to movewith respect to the wastegate seat 1426.

As an example, an assembly can include a turbine housing that includes abore, a wastegate seat and a wastegate passage that extends to thewastegate seat; a bushing configured for receipt by the bore; arotatable wastegate shaft configured for receipt by the bushing; awastegate arm extending from the wastegate shaft; and a wastegate plugextending from the wastegate arm where the wastegate plug includes acontact portion that contacts the wastegate seat to cover the wastegatepassage in a closed state and a shell portion that extends into thewastegate passage in the closed state and that defines a clearance withrespect to the wastegate seat in an open state. In such an example, thewastegate shaft, the wastegate arm and the wastegate plug may be aunitary component.

As an example, a shell portion of a wastegate plug may be or include anapproximately hemispherical shell. As an example, a contact portion of awastegate plug may be or include a radiused surface.

As an example, a wastegate seat may include a profile defined in part bya cone.

As an example, an assembly may include a control arm operatively coupledto a wastegate shaft. In such an example, an axial clearance may existbetween a surface of the control arm and an end surface of a bushingthat allows for self-centering of a contact portion of a wastegate plugwith respect to a wastegate seat.

As an example, a wastegate shaft may include an axis and a bore mayinclude an axis. In such an example, for a predetermined angularmisalignment of the axes, a wastegate plug, along a contact portion, maycontacts a wastegate seat to cover a wastegate passage (e.g., optionallyvia self-centering responsive to force).

As an example, a wastegate shaft may include an axis and a bore mayinclude an axis. In such an example, for a predetermined displacementmisalignment of the axes, a wastegate plug, along a contact portion, maycontact a wastegate seat to cover a wastegate passage (e.g., optionallyvia self-centering responsive to force).

As an example, an assembly can include a turbine housing that includes abore, a wastegate seat and two wastegate passages that extend to thewastegate seat; a rotatable wastegate shaft configured for receipt bythe bore; a wastegate arm extending from the wastegate shaft; and awastegate plug extending from the wastegate arm where the wastegate plugincludes a contact portion that contacts the wastegate seat in a closedstate and two shell portions that define clearances with respect to thewastegate seat in an open state. In such an example, at least thewastegate arm and the wastegate plug may be a unitary component.

As an example, each of two shell portions may be or include a portion ofa substantially hemispherical shell.

As an example, a turbine housing may include a divider wall disposedbetween two wastegate passages. In such an example, a wastegate plug mayinclude a gap between two shell portions where the gap accommodates thedivider wall in the closed state of the two wastegate passages.

As an example, in a closed state of two wastegate passages, each of twoshell portions of a wastegate plug may extend at least in part into arespective one of the wastegate passages.

As an example, an assembly may include a control arm operatively coupledto a wastegate shaft that is operatively coupled (e.g., optionallyintegral to) an arm and a plug where the plug includes a contact portionand two shell portions. In such an example, an axial clearance may existbetween a surface of the control arm and an end surface of a bushing(e.g., that receives the shaft) where the axial clearance allows forself-centering of the contact portion of the wastegate plug with respectto the wastegate seat (e.g., axial movement of the shaft).

FIG. 15 shows an enlarged cutaway view of a portion of the assembly 200of FIG. 2. As shown, the plug 256 seats in the wastegate seat 226 toseal the wastegate passage defined by the wastegate wall 223, which ispart of the turbine housing 210.

FIG. 16 shows a plan view and a side view of the wastegate arm and plug250 of the assembly of FIG. 2. As shown, the shaft 252 has a diameterD_(s) over a length Δz_(s). The arm 254 extends axially outwardly awayfrom the shaft 252 from a shoulder 255 and radially downwardly to theplug 256. An axial dimension Δz_(a) is shown in the example of FIG. 16as being a distance from the shoulder 255 to a centerline of the plug256. The plug 256 is shown as having an outer diameter D_(po). Adimension ΔSP is shown in the plan view as an offset between the axisz_(s) of the shaft 252 and the centerline of the plug 256. The dimensionΔSP may be a leg of a triangle that, for example, defines a hypotenuseas a dimension between a rotational axis of the arm 254 and thecenterline of the plug 256. FIG. 16 also shows various other features,for example, shaft features such as shoulders, contours, etc.

FIG. 17 shows another side view of the wastegate arm and plug 250. Inthe example of FIG. 17, a profile of the plug 256 is illustrated thatincludes a conical portion and a radiused portion that may define aninner diameter D_(pi). As shown, the conical portion may be definedaccording to a cone angle ϕ_(p) while the radiused portion may bedefined with respect to a radius R. As an example, the radiused portionmay be referred to as a toroidal portion or a toroidal surface. Whilethe toroidal portion extends to a conical portion in the example of FIG.16, a toroidal portion may continue as a radiused portion or extend to anon-conical or other portion. As an example, a plug can include toroidalsurface disposed between an inner diameter and an outer diameter of aplug (e.g., a toroidal surface disposed between D_(pi) and D_(po)).

FIG. 18 shows a cutaway view of the turbine housing 210, particularly toshow a relationship between the bore 212 and the wastegate seat 226 asthese features cooperate with a wastegate arm and plug such as thewastegate arm and plug 250. As shown in the example of FIG. 6, thewastegate wall 223 extends to the wastegate seat 226, which includes adiameter D_(o) of a cone section disposed at a cone angle ϕ_(o). As anexample, an assembly may include a plug with a cone portion having acone angle of about 60 degrees while a wastegate seat includes a coneportion with a cone angle of about 100 degrees. In such an example,contact may or may not occur between the two cone portions as sealingmay be achieved by contact between a toroidal portion of the plug andthe cone portion of the wastegate seat.

As an example, a wastegate arm and plug may include extreme positionsinside a bushing disposed in a bore of a turbine housing while beingable to maintain contact with a wastegate seat for purposes of sealing awastegate passage (e.g., adequate sealing for acceptable performance).

FIG. 19 shows examples of a wastegate arm and plug 1950 and 1970, whichmay be a unitary wastegate arm and plug or a wastegate arm and plugassembly. As an assembly, a plug portion 1956 may include an attachmentbase 1972 or 1992 from which a stem 1974 or 1994 extends where an arm1970 or 1990 fits to the stem 1974 or 1994, which is secured to the stem1974 or 1994 via an attachment component 1976 or 1996 (e.g., a press-fitring, etc.). In the example wastegate arm and plug 1970, a surface of anattachment base 1992 may be defined at least in part by a portion of asphere. In such an example, the arm 1990 may include a surface definedat least in part by a portion of a sphere. In such an example, somepivoting may be provided for the plug portion 956 with respect to thearm 1990 (e.g., as provided by some amount of clearance or clearanceswith respect to the stem 1994).

In the example of FIG. 19, the plug portion 1956 includes a toroidalportion “t” and, for example, optionally a conical portion “c”. Asshown, the optional conical portion may be defined by an angle ϕ_(c), aheight h_(c), and at least one of a lower diameter D_(cl) and an upperdiameter D_(cu). In the example of FIG. 19, the toroidal portion may bedefined by a diameter D_(t) and a radius r_(t), for example, where thetoroidal portion may be defined by a circular torus.

FIG. 20 shows some examples of toroidal portion profiles of a plug 2010,2020, 2030 and 2040 along with some examples of seat profiles 2015,2025, 2035 and 2045. Also shown in FIG. 20 are gridded surfaces that mayapproximate respective toroidal portions.

As to the example profile 2010, the toroidal portion corresponds to acircle, as to the example profile 2020, the toroidal portion correspondsto an ellipse, as to the example profile 2030, the toroidal portioncorresponds to an inwardly tilted ellipse and, as to the example profile2040, the toroidal portion corresponds to an outwardly tilted ellipse.In the examples 2010, 2020, 2030 and 2040 of FIG. 20, a thick solid linerepresents a profile that may be a profile of a plug, for example, suchas the plug 256. As to the seat profiles 2015, 2025, 2035 and 2045, thedotted lines may represent a profile that may be a profile of a seat,for example, such as the seat 226.

FIG. 21 shows some examples of seat profiles of a wastegate seat 2110,2120, 2130 and 2140 along with some examples of plug profiles 2115,2125, 2135 and 2145. Also shown in FIG. 21 are gridded surfaces that mayapproximate respective seat profiles. As to the example profile 2110,the seat may be defined by a toroidal portion that corresponds to acircle, as to the example profile 2120, the seat may be defined by atoroidal portion that corresponds to an ellipse, as to the exampleprofile 2130, the seat may be defined by a toroidal portion thatcorresponds to an outwardly tilted ellipse and, as to the exampleprofile 2140, the seat may be defined by a toroidal portion thatcorresponds to an ellipse (e.g., rotated 90 degrees in comparison to theexample 2120). In the examples 2110, 2120, 2130 and 2140 of FIG. 21, athick solid line represents a profile that may be a profile of a seat,for example, such as the seat 226. As to the plug profiles 2115, 2125,2135 and 2145, they may be a profile of a plug, for example, such as theplug 256. As shown in FIG. 21, a plug may include a conical profile or aspherical profile. As shown in various other examples, a plug mayinclude a toroidal profile.

FIG. 22 shows some examples of turbine wastegates 2210, 2230 and 1250.In the example 1210, a plug 1212 includes a conical shape and a seat2214 includes a radiused shape (e.g., a portion of a toroidal surface).In the example 2230, a plug 2232 includes a radiused shape (e.g., aportion of a torodial surface) and a seat 2234 includes a conical shape.In the example 2250, a plug 2252 includes a radiused shape (e.g., aportion of a spherical surface) and a seat 2254 includes a conicalshape. In the examples of FIG. 22, a torus may be defined by a radius(or major and minor axes) and a diameter and a sphere may be defined bya radius; noting that a spherical section may be defined by a surfacecutting a sphere. As an example, a cone or conical portion may bedefined by an angle and an axis and, for example, a position orpositions along the axis.

As an example, an assembly can include a turbine housing that includes abore, a wastegate seat and a wastegate passage that extends to thewastegate seat; a bushing configured for receipt by the bore; arotatable wastegate shaft configured for receipt by the bushing; awastegate arm extending from the wastegate shaft; and a wastegate plugextending from the wastegate arm where the wastegate plug includes aprofile, defined in part by a portion of a torus, for contacting thewastegate seat to cover the wastegate passage. In such an assembly, thewastegate shaft, the wastegate arm and the wastegate plug may be aunitary component.

As an example, a wastegate plug can include a profile defined in part bya portion of a cone. As an example, a wastegate seat can include aprofile defined in part by a cone.

As an example, wastegate plug can include a profile defined in part by aportion of the torus where that portion is disposed between an innerdiameter and an outer diameter of the wastegate plug.

As an example, an assembly can include a wastegate shaft with an axiswhere a turbine housing includes a bore with an axis. In such anexample, for a predetermined angular misalignment of the axes, awastegate plug connected to the wastegate shaft can include a profiledefined in part by a portion of a torus where along that profile, thewastegate plug provides for contacting a wastegate seat to cover awastegate passage.

As an example, an assembly can include a wastegate shaft with an axiswhere a turbine housing includes a bore with an axis. In such anexample, for a predetermined displacement misalignment of the axes, awastegate plug connected to the wastegate shaft can include a profiledefined in part by a portion of a torus where along that profile, thewastegate plug provides for contacting a wastegate seat to cover awastegate passage.

As an example, a wastegate plug may include a profile defined in part bya torus, for example, an elliptical torus having a minor axis lengththat differs from a major axis length. In such an example, an ellipticaltorus may include a tilt angle (e.g., where the major axes are notparallel).

As an example, a profile of a wastegate plug can include a conical angledefined by a tangent to a maximum outer diameter of the torus. In suchan example, a wastegate seat can include a conical angle where theconical angle of the wastegate seat exceeds the conical angle of thewastegate plug.

As an example, an assembly can include a turbine housing that includes abore, a wastegate seat and a wastegate passage that extends to thewastegate seat; a bushing configured for receipt by the bore; arotatable wastegate shaft configured for receipt by the bushing; awastegate arm extending from the wastegate shaft; and a wastegate plugextending from the wastegate arm where the wastegate plug includes aprofile, defined in part by a portion of a sphere, for contacting thewastegate seat to cover the wastegate passage. In such an example, thewastegate shaft, the wastegate arm and the wastegate plug may be aunitary component. As an example, a wastegate seat can include a profiledefined in part by a cone while a wastegate plug can include a profiledefined at least in part by a sphere. As an example, a wastegate shaftcan include an axis and a bore for receipt of the wastegate shaft caninclude an axis where, for a predetermined displacement misalignment ofthe axes, a wastegate plug, along a profile defined in part by at leasta portion of a sphere, provides for contacting a wastegate seat to covera wastegate passage. In such an example, the wastegate seat may includea portion defined at least in part by a cone.

As an example, an assembly can include a turbine housing that includes abore, a wastegate seat and a wastegate passage that extends to thewastegate seat, where the wastegate seat includes a profile, defined inpart by a portion of a torus; a bushing configured for receipt by thebore; a rotatable wastegate shaft configured for receipt by the bushing;a wastegate arm extending from the wastegate shaft; and a wastegate plugextending from the wastegate arm where the wastegate plug includes aprofile, defined in part by a portion of a cone, for contacting thewastegate seat to cover the wastegate passage. In such an example, thewastegate shaft, the wastegate arm and the wastegate plug may be aunitary component. As an example, a portion of a torus can include aportion of an elliptical torus having a minor axis length that differsfrom a major axis length. In such an example, the elliptical torus mayinclude a tilt angle.

As an example, a wastegate shaft can include an axis and a bore forreceipt of the wastegate shaft may include an axis where, for apredetermined displacement misalignment of the axes, a wastegate plug,along a profile defined in part by a portion of the cone, provides forcontacting a wastegate seat, along a profile defined in part by aportion of a torus, to cover a wastegate passage.

Although some examples of methods, devices, systems, arrangements, etc.,have been illustrated in the accompanying Drawings and described in theforegoing Detailed Description, it will be understood that the exampleembodiments disclosed are not limiting, but are capable of numerousrearrangements, modifications and substitutions.

What is claimed is:
 1. A turbocharger wastegate assembly comprising: aturbine housing that comprises a chamber, a bore, two exhaust passages,a divider wall disposed between the two exhaust passages, and awastegate seat, wherein the divider wall comprises a divider wallsurface; and a wastegate that comprises a shaft, an arm and a plug,wherein the shaft is received by the bore of the turbine housing forrotation about an axis of the shaft to orient the plug in a closed stateand to orient the plug in an open state, wherein, in the closed state, acontact portion of the plug contacts the wastegate seat and a shellportion of the plug defines a clearance with respect to the divider wallsurface and extends into the two exhaust passages.
 2. The turbochargerwastegate assembly of claim 1 wherein the contact portion defines aplane, wherein the plug comprises a plug axis perpendicular to theplane, and wherein the shell portion extends a distance along the plugaxis axially away from the plane.
 3. The turbocharger wastegate assemblyof claim 2 wherein, in the closed state, the shell portion defines theclearance with respect to the divider wall surface along the plug axis.4. The turbocharger wastegate assembly of claim 3 wherein the shellportion comprises a substantially planar surface at a position along theplug axis, wherein the divider wall surface comprises a substantiallyplanar surface, and wherein, in the closed state, the clearance isdefined between the substantially planar surface of the shell portionand the substantially planar surface of the divider wall surface.
 5. Theturbocharger wastegate assembly of claim 1 wherein, in the closed state,a corner portion of the shell portion is disposed in one of the twoexhaust passages and another corner portion of the shell portion isdisposed in the other of the two exhaust passages.
 6. The turbochargerwastegate assembly of claim 1 wherein the contact portion is part of arim of the plug wherein the shell portion extends away from the rim. 7.The turbocharger wastegate assembly of claim 1 wherein the wastegateseat comprises a conical profile.
 8. The turbocharger wastegate assemblyof claim 1 wherein the contact portion of the plug comprises a profilethat is a portion of a torus.
 9. The turbocharger wastegate assembly ofclaim 1 wherein the two exhaust passages are in fluid communication withdifferent exhaust passages of an exhaust manifold.
 10. The turbochargerwastegate assembly of claim 1 wherein the turbine housing comprises twovolutes.
 11. The turbocharger wastegate assembly of claim 10 whereineach of the two volutes is in fluid communication with a respective oneof the two exhaust passages.
 12. The turbocharger wastegate assembly ofclaim 1 wherein, in the closed state, the shell portion does not contactthe turbine housing.
 13. The turbocharger wastegate assembly of claim 1wherein, in the closed state, the shell portion does not contact thewastegate seat.
 14. The turbocharger wastegate assembly of claim 1wherein, in the closed state, the clearance resists flow of exhaust fromone of the two passages to the other of the two passages.
 15. Theturbocharger wastegate assembly of claim 1 wherein, in the closed state,the clearance is less than a thickness of the shell portion of the plug.16. The turbocharger wastegate assembly of claim 1 wherein the shellportion comprises halves wherein, in the closed state, one of the halvesextends into one of the two exhaust passages and the other of the halvesextends into the other of the two exhaust passages.
 17. The turbochargerwastegate assembly of claim 1 wherein the wastegate is a monoblockwastegate.
 18. The turbocharger wastegate assembly of claim 1 whereinthe shaft, the arm and the plug are a unitary piece of material.